Improvement in screw-drivers



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."MUNRO reW-Dljiv No.*2oo,147. Patented Feb. 26,1878.

[7M/(w for METERS, PHOTO-Lm*o UNITED STATES PATENT FFICE.

RODERIGK MUNROE, OF FITGHBURG, MASSACHUSETTS.

IMPROVEMENT IN SCREW-DRIVERS.

Specification forming part of Letters Patent No. 200, 747, dated February 26, 1878,' application led September 22, 1877.

To all whom it may concern:

Be it known that I, BoDERIoK MUNROE, of Fitchburg, in the county of Worcester and State of Massachusetts, have invented a new and useful Improvement in Screw-Drivers, of which the following is a description sufficiently full, clear, and exact to enable any person skilled in the art or science to which my 4invention appertains to make and use the same, reference being had to the accompanying drawings, forming a part of this specification, in which- Figure 1 is a sectional view lengthwise through the center of my improved screwdriver. Fig. 2 is an elevation.

My invention relates to that class of screwdrivers used by carpenters and others.

Heretofore such screw-drivers have been made with the blade stationary in the handle, and when in use the -handle had to be let go for a new hold at every half-turn given the screw, which is objectionable, particularly so in working overhead, as the hand loosens its grasp at every half-turn, as stated.

Several methods of grooving, chamfering, and flattening the handle have also been used, which are objectionable, as they tend to blister the hand, and do -not overcome the abovestated objections.

The object of my invention is to secure a firm grasp for the hand, giving more power with less effort, preventing the slipping of driver out of slot in screw, and making it perfectly easy and sure to use with one hand, while the other hand is engaged in holding the work, or otherwise.

The extreme simplicity of my invention obviates the necessity of a lengthy description.

In the drawings, letter A is a round steel blade attened to a point. C is a ratchet-ferrule, firmly attached to blade by means of a key. (Not shown.) B is a wooden handle. D is a ratchet-ferrule attached to handle, and its and operates in ratchet G. E is a groove surrounding the blade-shaft. F is a steel pin connecting ferrule D to handle, and for the groove E to play up and down on when in actual use. G is a spiral spring for the purpose of uthrqw'iiig the ratchets C and D apart when 1n actual use. p y

Theoperation of the device is as follows: When. the hand grasps the handle it holds it firmly, and the ratchet D operates on ratchet C to turn the blade A, and requires onlya forward and backward motion of the hand, without letting go the hold, as in former devices.

My invention is an improvement on the patent of Oliver Bond, No. 20,619, of June 22, 1858. I do not claim any of the improvements on the Bond patent shown in the patent of King, No. 126,716, of May 14, 1872.

What I do claim is- The combination of the blade A, having a ratchet-ferrule firmly attached thereto, the handle B, with its ratchet-ferrule rmly attachedfthe spring Gr in the handle, above the shank of the blade, and the pin F, extending across a groove in the shank, to allow a limited play to the latter, all substantially as shown and described.

RODERIOK MUNBOE.

Witnesses:

CHARLES FINDER, JAMES B. SARGENT. 

